Even if the FCC makes rules prohibiting broadband providers from selectively blocking or slowing some Internet traffic, other parts of the Internet will continue to give some traffic priority over other traffic, said David Farber, an engineering and public policy professor at Carnegie Mellon University.

Net neutrality rules, if they were applied across the Internet, could "slow things down incredibly," Farber said during a forum on network management and Internet content at George Washington University in Washington, D.C. In addition, U.S. Internet traffic can route through other countries, and it'd be impossible for the FCC to enforce Net neutrality rules there, he said.

Internet users are moving away from using mainly browsers and e-mail clients, and services such as videoconferencing will require dedicated bandwidth, added Richard Bennett, a network engineer and research fellow at the Information Technology and Innovation Foundation, a tech-focused think tank. Internet standards allow Web traffic to be prioritized, and it makes no sense to regulate that functionality out of the Internet, he said.

"Applications don't all have the same requirements," Bennett added. "Applications don't all have the same [bandwidth] cost."

Thursday's forum came a week after the FCC voted to begin a proceeding that would create new Net neutrality rules. New rules are needed to protect consumers and preserve innovation from Web application providers, FCC chairman Julius Genachowski said last week.

Other speakers at Thursday's forum said the concerns expressed by Farber and Bennett were unfounded. The proposed FCC rules don't attempt to impose Net neutrality across all parts of the Internet, instead prohibiting broadband providers from selectively blocking traffic they don't want to carry, said Harold Feld, legal director of Public Knowledge, a digital rights group.

Feld disputed concerns expressed by some panelists that Net neutrality rules would discourage investment in broadband networks. Mobile-phone carriers ran into network congestion problems in the late '90s, but had FCC rules in place saying they had to carry all traffic, he said. Instead of blocking traffic, they built out their networks and acquired more spectrum as a way to deal with the congestion, he said.

Major communications networks in the United States have always been open and nondiscriminatory, added Robb Topolski, chief technologist for the Open Technology Initiative of the New America Foundation. Broadband providers should be able to manage their networks but do it without discriminating against some Web applications or content, he said.

The FCC isn't telling broadband providers that they can't provide managed services for high-priority traffic, Topolski said. But the FCC rules would say that broadband providers can't block or slow certain types of traffic on the common Internet, he said.

But Farber questioned the need for new rules, with only two examples of a broadband provider blocking or slowing traffic in recent years. If the FCC continues to challenge bad behavior, as it has done in the past, broadband providers can continue to experiment with network management methods.

Broadband "companies have been reasonable," he said."There are a lot of techies who'd be happy to scream bloody hell if they do something bad."